Electric cable



Nov. '8, 1927.

H. W. FISHER ELECTRIC CABLE Filed Jan. LL92? FIEI.

FIEJI.

INVENTOR Patented Neve 8, i927.

HENRY W. FISHER, 6F YEBTH .QJfiBGY, HEW JERSEY, .QSQSIGHQLR T UTSZDER- GROUND CABLE CGMPANY, 0F PITTSBURGH,

PEIZNSYLVAEIA.

,g t filed January 232?.

My invention relates to the building of electric cables, and consists both in a structure and in a method of procedure, whereby a cable of superior quality is'obtained, The

' trating an alternative structure adapted to the same end.

When in the course of cable making the cable body, consisting essentially of the insulation-en eloped conductor or conductors,

goes throu h the lead press to receive its sheath of lead, the lead is necessarily warm.

Indeed, as the sheathed (and finished) cable comes from the press, it is quite hot. As it comes from the press the cable is as a matter of convenience wound on a reel. The ends of a length of cable are not in usual practice sealed, until the cable hascooled approximately to room temperature. in the cooling of the cable there is necessarily some contraction of the insulating compound within the cable structure. The ends oi the length of cable being-open, the cooling cable is, because of the contraction oi the body of fluid insulation within it, liable to absorb air. If, to prevent such absorption, the ends of the length of cable were closed before cooling, then the eflect of contraction of the fluid insulation would be likely to be the opening of void spaces within the body of the cable. The presence of spaces within the body of the cable, whether filled w1th air or void, is of course undesirable.

According tomy invention as it 1s lllustrated in Fig.1, when about to sheath a length of cable body in lead, I first shoot a few feet of lead through the lead press, forming thus an open pipe of lead. This open pipe I seal at the outer end. I then fill the pipe with compound, and then lmnsrnvnnra, conrefaarron or :sririozrlarc Serial li o. 163,845.

troduce the end or the cable body into the lead press and proceed with the operation of sheathing the cable in the usual manner. When the length of cable has been sheathed throughout, the sheath may be prolonged somewhat beyond the end of the cable body, and the pipe so formed may be filled. with compound and then closed.

I shows diagrammatically a singleconductor cable including aconductor l, and envelope of insulation 2, which may be understood to be wrapped-on paper tilled with insulating compound, and a'lead. sheath 3. lhe lead sheath is prolonged beyond'the end of the cable body in a pipe-like extension, closed at the remote end and filled with a body l of insulating compound. While the cable is being sheathed in lead, pressure is maintained upon the liquid which fills the body of insulation 2, and means may be provided for cooling the still unsheathed portion of the cable body.

The cable, being formed in the manner described, it becomes possible to reduce the volume of the contents of the cable sheath, in accordance with the thermal contraction oi such contents. Any convenient compression or constriction affording device or expedient may be resorted to. By way of example, I have in the accompanying drawing indicated a pair of rolls "lhese rolls may be mounted in housings to define a rollpass of a width equal to twice the thickness of the cable sheath, or more. This pair of rolls is caused to engage the extension of the cable, in the manner shown, and as cooling progresses the rolls are caused to advance upon and to crush the cable-end. Such advance of the rolls upon the cableend (or such advance of the cable-end into the roll pass) will progress slowly, and, as a. matter of practice may be continuous or intermittent.

Turning now to Fig. 11, an alternative structure is shown, adapted to accomplish the same general ends as in Fig. I are accomplished by the rolls 5, operating in the manner described. After the forward end of the cable has'passed through the lead press it is swung to vertical position, the oil-filled terminal portionv is cut off square near the tip, and a plug 6 is soldered to place in the cut off end. This plug, otherwise closing the cable end, is perforate, and in the perforation is set a connection 7 for an ward until oil comes out through the outer may similarly be providedwith a reservoir end. Thus the complete filling of the connection with oil may be insured.

The grease gun provided with the usual flexible hose is filled with oil, and before applying it, oil is forced out through the hose,

and when the connecting parts are thus flushed with oil, the gun is attached to connection 7. The

dicated upon gauge 9, reaches a certain value. It will ordinarily then be convenient to take the grease gun away, and to secure the cable end with thepressure gauge connected to 1t as indicated in Fig. II, to the reel upon which the cable as it comes from the lead press is progressively wound. When in the progress of sheathing, and as the finished portion of the cable increases 1n length and grows cold, the reading of the gauge will indicate shrinkage of the body of liquid within. The lead press may then be stopped and the grease gun may again be .connectedand the deficiency of'oil ma be made good and pressure may again be uilt up within thecable to the desired point. The gun may then again be taken away and the operation ofsheathing be recommenced.

As soon as the entire length of cable has been lead covered, its last completed end of oil closed with a similar plug, and through a that plug also a' grease gun may be connected, and by the operation of the guns shrinkage of the-oil incident to cooling may be made good.

' In order to hasten the cooling operation water may be caused to stream over the cable as it comes from the lead press, and of course gun is then operated, until' the pressure exerted upon the body of oil, 111- the same time a liquid which, being brought into immediate contact with the cable insulation, has no injurious effect upon that insulation; and aliquid which, to the. extent that it enters into and becomes part of the cable insulation, itself possesses adequate insulating properties.

I have shown, by way of example merely, a single-conductor cable, and a cable whose conductor is enveloped in wrapped-on insulation. Manifestly, the invention is applicable to any fluid-containing, lead-sheathed cable, whether single-conductor or multi-conductor.

I claim as my invention:

1. The method herein describedof maintaining the integrity of a body of fluid insulation within a sheathed cable as it comes hot from the. lead press which consists in exerting pressure upon a body of fluid insulation within a terminal prolongation ofthe cable sheath.

'2. The method herein described of. preventing fiaws in the fluid containing insulation of a cable while cooling which consists in maintainin pressure upon a body of fluid insulation wit in a terminal prolongation of the cable sheath while c'oolin is-in progress.

3. A cable length inclu ing conductor, fluid-containing insulation envelope, and lead sheath, the sheath being prolonged as a closed sack beyond the end of the insulating envelope and the sack so formed being filled HENRY W. FISHER. 

